Question

Which of the following is the most effective way to avoid damage to an X-ray tube focal track?

a)              Selecting as large a focal spot as possible

b)              Selecting as small a focal spot as possible

c)              Changing the oil around the tube regularly

d)              Keeping the tube as cool as possible when not using it

e)              Waiting for the light source in the light beam diaphragm box to go off before exposing

Answer 1

b)selecting as a small focal spot as possible.

To produce x-radiation, relatively large amounts of electrical energy must be transferred to the x-ray tube. Only a small fraction (typically less than 1%) of the energy deposited in the x-ray tube is converted into x-rays; most appears in the form of heat. This places a limitation on the use of x-ray apparatus. If excessive heat is produced in the x-ray tube, the temperature will rise above critical values, and the tube can be damaged. This damage can be in the form of a melted anode or a ruptured tube housing. In order to prevent this damage, the x-ray equipment operator must be aware of the quantity of heat produced and its relationship to the heat capacity of the x-ray tube.